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(N0 Modgl.) 2' SheetrS-Sheet 1.

VALVE GEAR.

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(N-o Model.) 2 Sheets-Sheet 2. J. FIELDING VALVE GEAR.

Patented Apr. 24, 1894.

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UNITED ySTATES,

ATENT OFFICE.

JOHN FIELDING, OF GLOUCESTER, ENGLAND.

VALVE-G EAR.

` SPECIFICATION forming part of Letters :Patent No. 518,593, dated April 24, 1894. APPIUBEOD led October 24, 1893. Serial No. 489.056. (No model.) Patented in England August l, 1893, No. 14,733.

To @ZZ whom it may concern.-

Be it known that I, JOHN FIELDING, of Gloucester, in the county of Gloucester,Eng land, have invented certain new and useful Improvements in Valve-Gear, (patented to me in `England August 1, 1893, No. 14333;) and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to an improvement in valve gear for duplex pumping engines, the objectof the same being to overcome a well known and material defect in the working of duplex pumps as ordinarily constructed and it consists in the parts and combinations of parts as will be more fully described and pointed out in the claims.

In the accompanying drawings Figure 1 is a view in end elevation partly in section of an engine embodying my invention. Fig. 1n is a View in section through the cylindrical bearing and showing the shaft therein. Fig. 2 is a side view of the parts shown in Fig. 1. Fig. 2fL is an end view of the parts shown in Fig. 1a, and Figs. 3, 4., 5 and 6 are views showing the movements of the valves.

In duplexpumps as ordinarily constructed, they are under some conditions liable towork short strokes, thus reducing their pumping capacity without a corresponding reduction in the consumption of steam. This defect arises from the action of the ordinary valve gear which causes each piston to reverse the valve of the opposite cylinder as it passes the half stroke; therefore as the valves are usually without lap, it is quite possible to have the piston make such short strokes that the pumping capacity may be reduced to a minimum without a corresponding reduction in the consumption of steam.

The steam cylinders A and B are placed side by side and are so combined as to act reeprocally upon the steam valves of each other. The piston rods C and C each carry a cross head a one of which connects with lever D and the other with lever D'. The lever D is provided at its upper end with a cylindrical enlargement or boss which forms a movable bearing ci which latter may be integral with the lever or keyed thereto, and is mounted in a bearing d rigidly secured in position to any convenient portion of the apparatus. This boss extends transversely across the apparatus,.and as the piston C to which lever D is connected, is reciprocated, it will be seen that the boss is given a semi-rotary movement in its bearing. This boss is provided as shown with an eccentrically located hole for the passage of shaft E, which latter is located parallel to the axis of the boss and in the same line radially as lever D.

Secured to shaft E is the second swinging lever D which latter is connected at its lower end to the cross head carried by the piston rod C. This shaft E is provided at either end with two short levers F F, placed in a line with lever D and opposite to each other. These levers operate the valves G and G by means of the connecting links g or their equivalent. As these levers stand opposite each other and are on opposite sides of the axis of shaft E, it follows that they move in opposite directions as the lever D vibrates. The result of this arrangement is that each valve, G and Gr', receives a compound movement partly due to that of the eccentric hole in the boss of the lever D, and partly to that of one of the short levers F F upon the shaft E. The action of the gear is such that each `piston reverses the valve of the opposite cylinder from full port open at one end to a slightlad opening at the other end, while it moves the valve of its own cylinder from the lead opening to full port opening. The movement of the parts is clearly shown in Figs. 3 to 6. These four figures show the positions occupied by the gear at the commencement of each of the four strokes which form the cycle.

In Fig. 3 the valve Gr is traveling from left to right j ust opening the left hand steam port and the right hand exhaust while valve G' is at the extreme left hand of its stroke the right hand steam and the left hand exhaust ports being fully open. `Now by moving lever D, which as before stated is actuated by one of the piston rods, the bodd d is turned in its bearing which shifts shaft E to the right, (without turning the said shaft) into the position shown in Fig. 4.-. In this ligure valve Gr is shown Wit-h its left hand steam and right hand exhaust open, while valve G has trav-` eled also from left to right enough to open left hand steam port and the right hand eX- haust slightly. The piston rod Which actuates lever `D now moves from left to right carryingwith its lever D', and the latter actuating shaft E and short levers F F moves the valve G from right to left and' the valve G from left to right as shown in Fig. 5 the posiin Fig. 3, now the movement of lever Dy from right to left brings the parts into .the positions shown in Fig. 6 Where they are exactly the reverse to those shownffin Fig. 4. The next movement of D from right toA left completes the cycle of movement and" brings 'the partsA l into the positions shown in Fig. 3;.` y

. operating edk eccentrically in a movable bearing, means g connecting one of the pistonmrods and shaft means connecting said movable bearing with j the otherpiston rod, and meansconnecting `Byrthe above arrangement 'of parts the valves'are lso connected and operated that their reversal cannotftake place until their stroke.

y Itislevidenrthatmanyslightchangesmight be resorted `to in the relative arrangement and construction of parts Without departing fromv the spirit and 'scope of my invention; hence I would have it understood that I do not restrict myself to the exact construction of parts herein described. n f y f Having fully described my invention, what I claim as new, and desire tosecnre by Letters Patent, isi f 1. "In a doiiblek cylinder engine thecombi` nation with Vtwo cylinders and a valve and piston rod for each cylinder of a shaft mounttions then being the reverse of those shown pistons havevjcompleted `their 'fnlL v specication the valves with the shaft, substantially set forth.k Y

2. In akdouhle cylinder' engine, the combii nation with the cylinders valves and piston rods, of amovable bearing a lever actuated.

by one of the pistons yfor giving said bearing a semi-rotary motion a shaft(` eccentrically mounted in said `movable bearing and 'provided with short levers, devices connecting` said short levers and valves and means actuatedby the other piston rod for rocking the shaft, substantially as set forth. i

In a double cylinder engine, the combination with .thecylinders valves and pistony rodsyof adcylinder boss or bearing a'lever ate Y tachedto said bosser kbearing .and engaging y one piston kroidta shaft eccentrically mounted valves, substantially `as set forth'. y

411.111 a double cylinder engine, the 'co1 `insaid* boss or hearing; a lever'V connected tog` i" said shaft'and actuated bythe otherpiston Y rod,.:`.1:id\devices yconnecting :the shaft and ,nation with the cylinders,l valves and piste v rods,` of a-cylindrical bosser bearing, a lever;` f

attached thereto and actuatedbyoneof the piston rods, afshaft eccentrically mounted in said boss or bearing and provided with short levers so located as to" move in opposite directions as the shaft is rocked, a leverconnected to said shaftand actuated by the other pistonil rod, and linksconneeting the short leversand valves, substantially as set forth. t f

-` In `testi fo'ny whereot'l have signedthisr Witnessesi .y y ,G. G.;BAKER, y y. o FRANK B. FIELDING. t

` Y in 4the presence of twosnbscrihjing witlynesses. V- 

